From time to time, it is necessary to weld two pieces of tubing of the same diameter end to end. The ends of the tubing to be joined are prepared prior to welding in order to obtain a strong weld. It is good practice to prepare the tube ends by forming an inside and an outside chamfer on each tube end. The inside chamfers receive a chill ring; and the outside chamfers form a symmetric welding notch when the tube ends are abutted for welding.
In the power-generating industry, internal pressures of more than 1,000 p.s.i. are sustained by boiler tube; such pressures are accompanied by high temperatures. Welds made in boiler tube would be called upon to withstand high pressures and temperatures.
The present methods of preparing boiler tube ends for welding are inefficient. A common method of preparing boiler tube ends for welding involves forming the inside chamfer and the outside chamfer in separate operations. The inside chamfer is formed by a conical cutter. The outside chamfer is formed by a device similar to the one herein disclosed, but having a single outside chamfer cutter. The present methods of preparing boiler tube ends are time-consuming because they involve two steps. Since the chamfer-forming operations are performed independently, there is a likelihood that the inside and outside chamfers will not be concentric; and may even be skewed. If the chamfers are non-concentric, skewed or both, the weld subsequently formed may have diminished structural integrity.